/Engine/Plugins/Animation/MLDeformer/MLDeformerFramework/Source/MLDeformerFramework/Public/MLDeformerModel.h
Update the cached number of target mesh vertices. Every model needs to implement this. The number of vertices should be the number of DCC vertices, so not the number of render vertices. This just updates the NumTargetMeshVerts property.
virtual void UpdateNumTargetMeshVertices()